Carburetor mixture control



Oct. 6, 1964 B. WALKER ETAL 3,151,604

CARBURETOR MIXTURE CONTROL.

Filed Aug. 27, 1962 5 Sheets-Sheet 1 /9 Fi .1. l

BROOKS WALKER FRANK W.KER7'ELL ATTORNEY Oct. 6, 1964 B. WALKER ETAL 3,151,604

' I CARBURETOR MIXTURE CONTROL Filed Aug. 27, 1962 3 Sheets-Sheet 2 BROOKS WAgERL FRANK sa L ATTORNEY Oct. 6, 1964 WALKER ETAL 3,151,604

CARBURETOR MIXTURE CONTROL Filed Aug. 27, 1962v 3 Sheets-Sheet 3 I I4 23 6:? u 64 1 e2 E ll A I i 60 33 .22 40 a 34 g f'fig.i

HOOKS WALKER RA/VK H. KERTELL w BY ATTORNEY United States Patent 3,151,604 CARBURETGR MEXTURE CONTROL rocks Walker, 1239 t'lolurnbus Ave, San Francisco, Calif and Frank W. Kerteil, Oakland, (jalih; said Kertell assignor to said Walker Filed Aug. 27, 1962, Ser. No. 219,476 9 Claims. (a. 123-1l9) This invention pertains to a mixture control for a carburetor, particularly when the idle air bypasses the main throttle butterfly.

On a normal carburetor the idle air passes by the main butterfly throttle and is choked by the offset butterfly choke in the air stream before the air reaches the throttle butterfly to effectively choke the air for idle or for limited power with the throttle partially open. In an anti-smog type carburetor where the fuel free air bypasses the main throttle the normal choke valve does not efiect a choke on the idle air which bypasses the main throttle butterfly. Such a carburetor is shown in Hall, US. Patent No. 2,809,623. The choking of the fuel free air for idle is accomplished in this invention in one of three ways, (1) taking the fuel free air from between the choke butterfly and the carburetor venturi so the main choke valve chokes the air that is bypassing the throttle butterfly; (2) having a secondary small choke butterfly operated by the same shaft that operates the main choke valve the secondary small choke in the passage for the idle air that bypasses the main throttle butterfly, the main choke butterfly shaft and secondary small choke shaft being essentially in line with each other; (3) a secondary small choke valve in the path of the idle air that is close to the idle air inlet below the main throttle butterfly and the small choke operated by a linkage to the main carburetor choke which is remote from the small choke. If the idle air is not choked on a cold start the engine will not start as well if the idle air that bypasses the main throttle butterfly is choked. Having the same automatic mechanism choke the idle air that bypasses the main throttle butterfly simplifies the construction over having separate automatic choke means for this idle air.

Another feature is to take the idle air from the crank case breathing and clean the excess through the main engine air cleaner.

Other features of the invention are more particularly pointed out in the accompanying specification and claims.

We have illustrated our invention by way of example in the attached drawings in which:

FIG. 1 is an elevation view partly cut away showing one form of the nvention.

FIG. 2 is a side elevation partly cut away of a portion of a carburetor embodying another form of this invention.

FIG. 3 is a side elevation of a portion of an engine and carburetor partly cut away showing a third form of this invention.

FIG. 4 is a side elevation partly cut away of a further form of the invention.

In all figures like numerals of reference refer to corresponding parts.

In FIG. 1 we have shown an engine 10, a carburetor 11, a venturi 12, a main choke valve 13, a choke shaft 14, an automatic bimetal hoke device (not shown in detail but illustrated in Glenns New Auto Repair Manual, page 237, paragraph 35l, 1961 edition). Beat for the automatic choke passes through tube 16 from pickup 17 in exhaust manifold 18. The main air for carburetor 11 comes through air cleaner 19. Crank case breathing goes through oil filler neck 21, oil filler cap 22, tube 23 to the air cleaner 1?. idle air enters through tube 24 past idle choke valve 25 through tube 25 to heater 2'7 in exhaust manifold 23, such as is used on each ice side of a V-type motor. Idle air then passes through tube 29, regulator valve with screw adjustment 31 to idle air orifice 32. Idle fuel enters passage 33 in the usual manner from the float bowl of carburetor 1i and is controlled by solenoid valve 35 to cut off the idle fuel.

on high speed decelerations and turn on the idle fuel to prevent stalling and for idle and cruises at power, by means well known in the anti-smog art. When the engine is cold automatic choke mechanism 15 moves choke 13 to the choked position and a connection to choke 25 through shaft 14 also chokes the idle air passing through tubes 24, 26, 2'7, 29, valve 3%, orifice 32, so that the one automatic choke mechanism 15 operates choke valve 13 and choke 25 on the same shaft 14. Adjustment for idle air is achieved by screw 31 in idle air valve 36. Main throttle valve 4%- is essentially closed at deceleration and idle operations.

In FIG. 2 the idle air is taken through port 41 below choke 13 and above venturi 12 through tube 42, heater 27 (if necessary the idle a r to heat), line 29, idle air adjustment valve 3t) and through orifice 32. Orifice 32 may be below idle fuel inlet 34 for improved mixing with idle air through port 32 while idling with main throttle valve substantially closed to prevent fuel from the main jets (not shown) in the venturi 12 from entering the en-.

gine while decelerating at high speeds with idle fuel shut ofi by solenoid 35 for improved anti-smog operation.

In FIG. 3 idle air comes from crank case ventilator pipe 21 and the excess desired for idle air comes from pipe 23 which is cleaned by air cleaner 1?. Such idle air passes through tube 4-5, heater 46 in exhaust manifold 47 (if heated idle air is desirable), through tube 4-8 to idle air valve 39 with adjustment screw 31 to idle air choke valve 49. Choke butterfly 50 is connected to main choke 13 by crank 52 (on main choke shaft 14), link 51 and arm 53 on the shaft that supports small choke 5:) so that the automatic choke mechanism 15 that operates choke 13 will simultaneously operate small choke 59 in the idle air path.

The idle air in these inventions uses some of the crank case breathing. The idle air is also cleaned by the main carburetor air cleaner 19 so that all of the crank case breathing is entered into the engine induction system for better combustion of the smog-producing components of the crank case breathing fumes.

In FIG. 4 the idle air is drawn through port between choke 13 and venturi 12. The idle air then passes through pipe 64, valve 62 with adjustment screw 63, tube 61 to port 69 below throttle butterfly 4t). Solenoid 35 controls the flow of idle fuel through port 34 located below idle air port 6%? to get good mixing of idle fuel and idle air. No heating of the idle air is provided in this invention but it can be added if desired. The choking of valve 13 by automatic choke mechanism 15 or by manual means (not shown) will also choke the idle air which bypasses the main throttle valve 4! The idle air and crank breathing are both cleaned by air cleaner 19.

We have illustrated our inventions in these various forms; however, many other variations may be possible within the scope of this invention.

To those skilled in the art to which this invention relates many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the spirit and scope of the invention. The disclosures and description herein are purely illustrative and are not intended to be in any sense limiting.

We claim as our invention:

1. An engine including a carburetor, a float bowl, a throttle butterfly valve in said carburetor, a choke butterfly valve in said carburetor, an idle jet, a first passage for fuel from said float bowl to said idle jet, a separate second passage for air from the engine. side of said choke butterfly around to the engine side of said throtfle butterfly, said second passage admitting the majority of air for. idling when said throttle butterfly is essentially closed, air passing to said engine through said second passage being. eflectively choked by said choke butterfly during choke operations said idle air'passage being separate from said idle fuel jet, so that the idle air passing through saididle. air. passage does not passthrough said idle fuel jet.

2. An engine. including a crank case, a carburetor, a main induction passage through said carburetor, a carburetor throat, a throttle. butterfly, a main choke butterfly, said throat, throttle and choke butterfly all. located in.said main induction passage in said carburetor, a crank .case breather connection, a separate passage around said throttle butterfly connected to said crank case breather connection, some breathing of said crank case passing through said separate passage and traveling around said throttle butterfly and. into said engine on the engine side of said throttle butterfly, operating means connected to said main choke butterfly to choke said main induction passage and simultaneously eflectively choke said separate passage between said crank case connection and 'where said separate passage connects to the engine side of said. throttle butterfly.

3'. A structure as described in claim 2 in which there main carburetor throat, a throttle butterfly, a crank case breather connection, two passages for conducting crank case breathing to said. carburetor to: be drawn into said engine, one path leading to the engine. side of said'throttle butterfly and subjectto operator engine suctions at the opening, into said carburetor throat below said throt tle butterfly, the. second passage connecting said crank case breathing to the intake tothe main throat of said carburetor.

5. A structure as described in claim 4 in which said engine includes an air cleaner, said air cleaner connected directly tothe main throat ofsaid carburetor, said sec-- 7. An engine including a crank case, a carburetor, a carburetor throat, a throttle butterfly, a main choke butterfly, a crank case breather connection, a passage around said throttle butterfly connected to said crank case breather connection, air entering said crank case passing through said passage around said throttle butterfly and. intosaid-carburetor near said. throttle butterfly.

on the; engine side of said throttlebutterfly, choke means connected to said main choke butterfly to choke said passage between said crank case connection and where said passage connects to the main carburetor throat on the engine side of said throttle butterfly, another connectionfrom said crank case, this connection including.

a passage leading from the crank case to the intake. to said carburetor to. lead any blowby from said crank case to said carburetor when said blowby exceeds the flow through said first passage which leads around said throttle butterfly to at, least oneport on the engine side of said engine butterfly.

8. An internal combustion engine, having a carburetor, said carburetor including a throttle .valve, a choke valve, a main fuel jet, anv idle-fuel jet, said idle-fuel jet ad.- rnitting said fuel on the, enginesside of said. throttle valve when said throttlev valve is in the engine idle position, an idle-fuel conduit supplying. fuel to said idle-fueljet, and an idle-air passage separate. fromsaid. idle fuel con duit, admitting idle-air on the engineside of said throttle.- V

valve, said separatew idle-air passage picking up its. air

on the engineside of said. choke valve so that said choke fuel in said carburetor, said carburetor including. a main.

air induction. passage,.a throttle valve, a main fuel jet,

an idle-fuel jet, said idle-fuel jet admitting said fuelon the engine side of said throttle valve when said throttle valve is in the engine. idle. position, an idle-fuel conduit supplying fuelv to saidv idle-fuel jet, an idle=air passage.

separate from said idle-fuel conduit, said idle-air passageadmitting idle-air on the engine side of saidthrottle. valve. after bypassing said. throttle valve, and choke means for.

simultaneously choking the air passing through said main induction passage and said separate idle-air passage, said idle air passage being separate from said idle fuel jet, so that the idle air passing through said idle. air passage. does not pass through said idle fuel jet.

References Cited in the file of this patent UNITED STATES, PATENTS 2,489,230 Winkler Nov. 22-; 1-949 2,516,547 Carlson et a1. July 25,- 1950 2,737,935

Olson Mar. 13, 1956 

1. AN ENGINE INCLUDING A CARBURETOR, A FLOAT BOWL, A THROTTLE BUTTERFLY VALVE IN SAID CARBURETOR, A CHOKE BUTTERFLY VALVE IN SAID CARBURETOR, AN IDLE JET, A FIRST PASSAGE FOR FUEL FROM SAID FLOAT BOWL TO SAID IDLE JET, A SEPARATE SECOND PASSAGE FOR AIR FROM THE ENGINE SIDE OF SAID CHOKE BUTTERFLY AROUND TO THE ENGINE SIDE OF SAID THROTTLE BUTTERFLY, SAID SECOND PASSAGE ADMITTING THE MAJORITY OF AIR FOR IDLING WHEN SAID THROTTLE BUTTERFLY IS ESSENTIALLY CLOSED, AIR PASSING TO SAID ENGINE THROUGH SAID SECOND PASSAGE BEING EFFECTIVELY CHOKED BY SAID CHOKE BUTTERFLY DURING CHOKE OPERATIONS SAID IDLE AIR PASSAGE BEING SEPARATE FROM SAID IDLE FUEL JET, SO THAT THE IDLE AIR PASSING THROUGH SAID IDLE AIR PASSAGE DOES NOT PASS THROUGH SAID IDLE FUEL JET. 